Full Mauna Loa CO2 record

The carbon dioxide data (red curve),
measured as the mole fraction in dry air, on Mauna
Loa constitute the longest record of direct measurements of CO2 in the
atmosphere. They were started by C. David Keeling of the Scripps Institution
of Oceanography in March of 1958 at a facility of the National Oceanic and
Atmospheric Administration [Keeling, 1976]. NOAA started its own CO2
measurements in May of 1974, and they have run in parallel with those made by
Scripps since then [Thoning, 1989]. The black curve represents the seasonally corrected data.

Data are reported as a dry mole fraction defined as the number of
molecules of carbon dioxide divided by the number of molecules of dry air
multiplied by one million (ppm).